1. Field of the Invention
The present invention relates to an ion implanter, a magnetic field measurement device, and an ion implantation method.
2. Description of the Related Art
It is known that a nuclear magnetic resonance probe is used to measure a magnetic field of an energy analyzer magnet in ion implanters. Principally, the method of measuring a magnetic field using the nuclear magnetic resonance probe is errorless. Because the method is capable of measuring a magnetic field of an energy analyzer electromagnet accurately, an ion implanter capable of analyzing energy with high precision can be provided.
In the magnetic field measurement using a nuclear magnetic resonance probe, a nuclear magnetic resonance absorption frequency is identified by sweeping high-frequency magnetic fields within a certain frequency range. Because the method requires such frequency tracking, a relatively long period of time is required for the measurement. The magnetic field measurement is performed in an example situation when a magnetic field of the electromagnet is established according to a specified condition for implantation. The magnetic field measurement and subsequent current adjustment of the electromagnet based on the measurement are generally repeated until a desired magnetic field is established. By establishing a magnetic field early, the ion implantation process can start early as well. Consequently, productivity of the ion implanter is improved.